1. Field of the Invention
The present invention relates to powder measuring and dispensing devices. More specifically, the present invention relates to devices for quickly and accurately measuring preselected amounts of gunpowder.
While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
2. Description of the Related Art:
The accurate loading of rounds is critical to the safe and effective operation of a firearm. Various techniques and apparatus for measuring and dispensing gunpowder are known in the art. U.S. Pat. No. 4,696,356 issued to Ellion et al. on Sept. 29, 1987, disclosed a particularly advantageous device which constituted a substantial improvement in the gunpowder dispensing art. In this reference, Ellion et al. provide an accurate, high speed automatic powder dispensing and measurement apparatus which includes coarse and fine motor driven threaded tubes or barrels. As the barrels rotate, powder is transferred from a chamber to a scale. An electronic circuit monitors the weight of the powder in the scale and controls the rotation of the barrels accordingly. That is, as the scale approaches the preselected amount of powder, the electronic circuit responds by slowing the rotational rate of the appropriate barrel. When the preset amount is reached, the circuit terminates the rotation of the barrels.
While the above-described apparatus substantially eliminated many of the problems with prior powder dispensing devices, a need remains in the art to further improve the speed, accuracy, reliability and performance of powder dispensers. For example, the Ellion apparatus uses electric motors with reduction gears to supply power. This is due to the fact that the control of the amount of powder dispensed with a reasonable degree of precision requires the coarse feed barrel to be limited to approximately 120 revolutions per minute (RPM) and the fine feed barrel to be limited to roughly 30 revolutions per minute. Electric motors rated in this range operate at dangerously high voltage and current levels for the gunpowder loading application. On the other hand, small electric motors that operate with reasonable voltage and current ratings run in the 3000 to 6000 RPM range. As a result, small motors must be used with gears or other speed reduction components. The preferred approach, therefore, involved the use of a high speed motor, having a high angular momentum, with a set of expensive reduction gears.
In addition to being costly, the speed reduction components add to the system momentum. The high angular momentum of such systems poses problems in that the barrels continue to rotate after power to the motors is cut off. Even with a bypass diode across the motor to dissipate the momentum energy, a considerable amount of powder is dispensed after power is shut off. The solution offered in the referenced patent is to provide a vertical adjustment for the fast feed barrel control sensor. Unfortunately, that solution merely provides a better anticipation of the amount of the overflow, but does not limit the momentum of the gear motor-barrel assembly. The amount of powder dispensed after the power is shut off is controlled more precisely but there is still a variation in the amount of overflow between each loading which is difficult to anticipate or control.
Other problems associated with the apparatus of the referenced patent include scale inertia and jamming. The scale inertia problem arises when powder is loaded on the scale at a high speed. Whenever, this occurs, the inertia of the scale is such that the scale does not respond fast enough to provide a sufficiently accurate reading throughout the loading process. Thus, the desired weight is reached before the scale is in a position to activate the cutoff sensor. The result is an undesirable overflow and/or an overshoot of the cutoff point with some vacillation thereabout.
The jamming problem may arise when cylindrically shaped powder is caught partially into the inlet port of the rotating barrel or when very fine powder enters the bushings.
There is therefore a need in the art for an inexpensive, reliable, accurate, high speed powder dispensing apparatus.
Thus, one objective of the present invention is to reduce the momentum of the feed barrel of an Ellion loader by orders of magnitude thereby causing the apparatus to cease dispensing powder as soon as the power is shut off.
Another objective of the present invention is to provide a method to cause the balance arm of the scale to move slowly and smoothly to the final zero balance position while dispensing a high rate of powder, thereby preventing the supply of powder exceeding the preselected amount.
Yet another object of the present invention is to eliminate the need to rotate the barrels to minimize the likelihood of occasional jamming.
Still another object of the invention is to provide an inexpensive apparatus for accurately dispensing powder at a high rate.